Introducing Ozone to Water Purification

InnovaMass® 240S Multivariable Vortex Mass Flow Meter

Traditionally, chlorine has been used to disinfect water for drinking. Unfortunately, chlorine produces carcinogenic by-products called trihalomethanes (THM’s) when it reacts with organic substances in surface waters. The recent adoption of the Surface Treatment Rules by the U.S. E.P.A. places strict limits on chlorine. Because ozone produces fewer disinfecting by-products, the EPA, along with the American Water Works Association, has emphasized the use of ozone as a highly desirable water treatment alternative.

Ozone has been used for more than 100 years to purify water by oxidizing minerals such as iron, manganese and hydrogen sulfide and by destroying bacteria, viruses and cysts. It is more than 3,000 times faster than chlorine and is the most powerful microbiocide commonly available for water treatment.

Man-made ozone is formed by passing dry ambient air or oxygen through a high voltage field called a corona, which is produced inside an ozone generator. The high voltage breaks apart the oxygen molecules and causes them to reform as ozone, which is up to 13 times more soluble in water than oxygen. Ozone generators require a known mass flow rate of the oxygen or air fed into the device. This measurement is required to prevent the device from becoming saturated so that the amount of ozone produced can also be measured.

SIERRA’S SOLUTION

As the EPA’s rules on disinfecting by-products get stricter, more water treatment facilities are opting to use ozone systems for water purification instead of chlorine. Sierra’s InnovaMass® helps water treatment plants precisely measure the flow rate of oxygen entering these ozone generators.

Measuring the amount of ozone produced by the ozone generator is problematic since the ozone has a short lifetime. It cannot be stored and needs a short "residence time" in the piping and flow meter. The Sierra InnovaMass vortex meter is an in-line device that is fully flow-profile compensated, so that minimal straight-run piping is required. Ozone is also produced at low pressures, so pressure drop losses must be minimized. The Sierra Vortex meter does not appreciably obstruct the pipe so pressure drops are also minimal.

The generator requires a robust flow device that is well shielded from the Coronal discharge that produced the Ozone. Housed in an explosion-proof enclosure, the Sierra InnovaMass vortex meter is virtually immune to the heavy electromagnetic interference (EMI) an ozone generator can produce.

Here’s what makes Sierra’s InnovaMass 240S an ideal choice:

Provides five process variables (mass flow, volumetric flow, pressure, temperature and density) at a single measurement point

Built-in pressure, temperature and flow profile compensation

All parameters are field adjustable and include complete field diagnostics